Application of a photosensitive resin insulating film produced from a photosensitive resin represented by a photosensitive polyimide resin having excellent mechanical properties and high heat resistance has been expanding, and starts to be spread not only in a semiconductor field but also in a display field, so that reliability on an insulating film which has never been required until today is required.
At present, many of positive photosensitive resin compositions used are produced by adding a photosensitive dissolution inhibitor (diazonaphthoquinone: DNQ) to a base material polymer. A positive pattern can be obtained by producing a coating film from this resin composition, followed by exposing the film to light through a mask, and dissolving the exposed part in tetramethylammoniumhydroxide (TMAH) which is a representative water-soluble alkaline developer.
Since a representative polyimide-based positive photosensitive resin composition has an excessively high solubility in TMAH, such a method is adopted that by reducing the acidity of a polyamide acid using a basic organic compound such as triethylamine, the dissolving rate of the composition in an alkaline developer is suppressed (Patent Document 1).
On the other hand, it is disclosed that since a polyhydroxyamide resin has an adequate solubility in TMAH, the resin is capable of being suitably utilized as a positive photosensitive resin composition (for example, Patent Document 2).
Examples of properties required to a positive photosensitive resin composition using a polyhydroxyamide resin include having film physical properties excellent in electric insulating properties, heat resistance, mechanical strength and the like, and being capable of forming a high-resolution circuit pattern. Recently, requirements for properties of these positive photosensitive resin compositions have become more rigid than ever.
Generally, a polyhydroxyamide resin is synthesized using a dicarboxylic acid chloride and dihydroxyamine under a basic condition (Non-patent Document 1). However, by this method, since inorganic ions such as chloride ions are present in the reaction solution, a polymer needs to be isolated and purified after the completion of the reaction. In addition, since inorganic ions are mixed in the positive photosensitive resin composition obtained, there is a problem that the inorganic ions cause corrosion when the positive photosensitive resin composition is used in an electronic material field.
For solving such a problem, there is disclosed a method for synthesizing a polyhydroxyamide using as a dicarboxylic acid component, a dicarboxylic acid derivative obtained from a reaction of 1-hydroxybenzotriazol with a dicarboxylic acid (Patent Document 3). However, since a leaving group derived from the dicarboxylic acid derivative is mixed in the reaction solution, a process for removing the leaving group becomes required, so that it is difficult to obtain a high-purity polyhydroxyamide.
On the other hand, there is also disclosed that a polyhydroxyamide resin synthesized from a coumarin dimer and a diamine is utilized as a negative photosensitive material (Patent Document 4).
However, until now, there has been no reported example for a composition containing a polyhydroxyamide resin and a compound generating an acid by light irradiation.    [Patent Document 1]    Japanese Patent Application Publication No. JP-A-62-135824    [Patent Document 2]    Japanese Patent Application Publication No. JP-A-2003-302761    [Patent Document 3]    Japanese Patent Application Publication No. JP-A-9-183846    [Patent Document 4]    Japanese Patent Application Publication No. JP-A-58-55926    [Non-patent Document 1]    Polymer Letter., Vol. 2, pp. 655-659 (1964)